Many micromirrors are designed using any one (or combination) of only a three primary styles of operation. First, the "phase-only" piston-style device, known as the Flexure-Beam micromirror, operates such that the motion of the reflective surface is along an axis orthogonal to its plane. The reflective mirror surface is attached to several identical flexures that support the mirror uniformly around its perimeter. As a result the direction of propagation is preserved and only the phase is modified by lengthening or shortening the optical path of the incident light.
The second design is a Cantilever micromirror which is probably the most common style. The mirror of this device is attached at one end by as little as a single flexure and is deflected downward at an angle as the device is actuated. This device alters the direction of propagation of an incident beam of light and also creates a non-uniform phase-front in the reflected light due to the slanting of the mirror surface.
The final design is the Torsion-Beam micromirror which is similar to the Cantilever device with the exception that the mirror is attached by two flexures opposite each other. As a result, this device rotates along the longitudinal axis defined by these flexures. The mirror surface tilts as with the Cantilever device, but it can be tilted in two directions along both sides of the flexures rather than just one.
But all of the above mirrors are limited in movement to one or two directions and there is need and market for micromirrors that have sufficient multi-movement capability as to overcome the above prior art shortcomings.
There has now been discovered micromirrors of multi-motion that can move to multi-positions as desired, so as to alter the phase, amplitude, and/or direction of propagation of incident light.